1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.ldap.model.schema.comparators;
21
22
23 import java.io.Serializable;
24
25 import org.apache.directory.api.ldap.model.schema.LdapComparator;
26 import org.slf4j.Logger;
27 import org.slf4j.LoggerFactory;
28
29
30 /**
31 * A comparator for Strings.
32 *
33 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
34 */
35 public class StringComparator extends LdapComparator<String> implements Serializable
36 {
37 /** The serial version UID */
38 private static final long serialVersionUID = 2L;
39
40 /** A logger for this class */
41 private static final Logger LOG = LoggerFactory.getLogger( StringComparator.class );
42
43
44 /**
45 * The StringComparator constructor. Its OID is the StringMatch matching
46 * rule OID.
47 */
48 public StringComparator( String oid )
49 {
50 super( oid );
51 }
52
53
54 /**
55 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
56 */
57 @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "ES_COMPARING_PARAMETER_STRING_WITH_EQ",
58 justification = "false positive")
59 public int compare( String s1, String s2 )
60 {
61 LOG.debug( "comparing String objects '{}' with '{}'", s1, s2 );
62
63 if ( s1 == s2 )
64 {
65 return 0;
66 }
67
68 // -------------------------------------------------------------------
69 // Handle some basis cases
70 // -------------------------------------------------------------------
71 if ( s1 == null )
72 {
73 return ( s2 == null ) ? 0 : -1;
74 }
75
76 if ( s2 == null )
77 {
78 return 1;
79 }
80
81 return s1.compareTo( s2 );
82 }
83 }